Make sure your LAN/WLAN and WiFi networks have the same level of permissions/connectivity. Often, administrators reduce access rights for WiFi networks (as they're less secure). For example, it may be necessary to setup extra VPN connection before you can access something in your LAN. So
- Contact your system administrators about the differences and gotchas
- Grab the traffic with help of WireShark or similar sniffer and compare both cases (LAN/WLAN and WiFi)